It's interesting, but I wonder how it is lubricated. Those two 'lobes' that
move back and forth as the ball turns each have to seal along a fairly long
dimension on the inside, in addition to the outer surface of the ball. It
was the seals on the wankle engine that created the largest design problem,
and initially wore prematurely. The cure for that was hardening and
treating the seals and chamber with a chrome alloy. But lubrication of the
seals was still a problem. The RX-7 had an oil injection pump that metered
oil into the incoming fuel/air mixture. This was one of the reasons why
they had a hard time passing CA emissions. They had to add a some serious
catalytic converters (pre-cat, cat, and cat back) to it, on mine the precat
had an air injection pump and got hot as hell. Like I said, lubrication was
key. Most owners added Marvel Mystery Oil to the gas. Typically the chrome
would start to flake off the rotor housing around the exhaust port.... which
would then cause wear on the apex seals.
Now that being said, the motor should run smooth as hell. All the mass is
being displaced equally and opposite from side to side along the axis of
rotation, not in and out from the axis. The only real vibration would be
from the ignition pulse.
Pretty cool.
Jeff